FOI request detail

London Bus telemetry data 2018-2022 inclusive

Request ID: FOI-2701-2223
Date published: 28 February 2023

You asked

Dear FOI team, I hope this message reaches you in good spirits and healthy databases. I'd like to analyse the telemetry data from London's bus fleet over the past 5 years. To what extent is this data collected, stored and used already? Thanks. Clarification received 26/01/2023: Thanks for getting back to me so swiftly. It's hard to know what to request specifically, because that would depend on the nature of contractual agreements, Key Performance Indicators and organisational resources. So in the spirit of wishing for the moon, ideally I'd like tables of bus numbers, high resolution time stamps, geographic lat/long and context comments (weather/traffic/mayhem). Clarification received 16/02/2023: Thank you for your response, to answer each point of clarification. bus number - the route of the bus (e.g. 179, W12). if it is too much to track down every single bus I could further specify a selection of bus routes. high resolution time stamps - I'd like to know if there is time and date value collected at key points during a typical bus journey. Perhaps the IT system logs the datetime at every stop, or every minute, or every ten minutes. I specify high resolution as a preference of resolution. Maybe the resolution TFL collects is minute level, maybe seconds. geographic lat /long - specifically of the bus in question along the journey in question context comments - in the tracker of daily report associated with the bus journey there might be comments about the context deemed noteworthy for Analysis (eg. fog, rain, roadworks, accident, traffic, passenger alarm). I hope this clarifies matters.

We answered

TfL Ref: FOI-2701-2223

Thank you for your request of 24th January 2023 (as clarified on 26th January and 16th February 2023) asking for bus telemetry data.
Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. 

Specifically you asked for the following, for every bus route and individual service that has run in London over the last 5 years:
  • the bus route number
  • every “time and date” stamp collected at any point;
  • every log of the bus’s position expressed as latitude and longitude
  • if comments are logged about any aspect of operation, for those comments to be provided

I am afraid that it is not possible to provide the requsted information within the costs limit for responding to FOI cases, as set out under section 12 of the Freedom of Information Act. Under section 12, TfL is not obliged to provide information if it woul cost more than £450 to determine if the information is held, and to then locate, retrieve or extract it from elsewhere. This is calculated at a rate of £25 per hour, equivalent to 18 hours work. The exemption applies in this instance due to the enormous volume of information covered in your request. Colleagues in our buses team estimate that just for a single day we will hold millions of items of such data. For example, for the timestamps element of the request, for just timestamps at bus stops alone (and not between bus stops) we hold around 3.5 million rows of data for one single day - and so for 5 years this would be around 6,387 million rows of data. It would take some considerable amount of time and resource to extract all of this data for every service across 5 years, and we estimate it would be well in excess of the costs limit.

In order to bring your request within the costs limit you may wish to reframe it to narrow its scope, focussing on the information that is of most imprtance to you. For example, rather than asking for data for every service for every day across five years it may be possible to provide a representative sample (such as for the same day - i.e 28th February - for each of the five years) or data for specific services only. Note that the narrower the scope of the request the more likely it is we will be able to respond positively within the costs limit. Note also that you may also find data that is of interest already published on our website - such as via the bus section of the following link:

Please see the attached information sheet for details of your right to appeal.

Yours sincerely,

David Wells
FOI Case Officer
FOI Case Management Team
General Counsel
Transport for London


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